Process for the duplication of sound recording tapes



Dc' 22, 1942- H. wEsTl-:RKAMP I 2,305,800

PROCESS FOR THE DUPLICATION OF SOUND RECORDING TAPES Filed June ll, 1959/n venan:

Patented Dec. 22, 1942 PROCESS FOR THE DUPLICATION F SOUND RECORDINGTAPES lingo Westerkamp, Cologne-Braunsield, Germany; vested in the AlienProperty Custodian Application June 1, 1939, Serial No. 276,927 InGermain' June 14, 1938 11 Claims.

The invention relates to a process for the duplication of sound tapeswith mechanical `sound recording by a master matrix of tape form.

Sound tapes with mechanical sound recording are generally produced bycutting sound grooves in a thin uniform layer oi' wax on a carrier oftape form. For the production of duplicates from such an original soundtape, a master matrix is prepared therefrom, for example byelectroplating, whichmay be employed as a master stamping matrix.However, considerable difficulties are encountered in pressing copiesfrom the master matrix owing to its tape form.

In contradistinction thereto, it is proposed in accordance with theinvention to spray or squirt onto the surface of the master matrixprovided with the sound tracks, a mass, for example a sprayable masshaving a cellulose base or an articial resin mass, capable oi beingsprayed 2 or squirted in such a thin layer that a iiexible v coating isformed which, when detached from the master matrix, may be directlyemployed as a sound tape.

It is to be noted that-the use of the spraying or squirting process hasalready been proposed for the duplication of sound discs. However,

whereas in such cases it is a question of vthev duplication of objectsof relatively small dimensions which are more or less rigid in theiinished state, a sound tape is an object which is generally severalmetres long and must be extremely flexible in the nlshed state in orderthat it may be wound up into a roll. By reason of'these differences, theidea of employing the spraying or squirting process also in theduplication of sound tapes has not been conceived, and it has vactuallynever been proposed to duplicate sound tapes by the spraying orsquirting process, although proposals for the simple and cheapproduction of copies of sound tapes have certainly not been lacking.

'Ihe process according to the invention is preferably carried out bywindingv up the master matrix into a roll with the interposition ofSpacing members, and iilling the space between the individual turns ofthe roll with a sprayed or squirted mass; to this end, the spacingmembers are given such dimensions that the space formed thereby betweenthe turns of the master matrix is equal to the thickness of the ilexiblesound tape to be produced.

For the production of endless crossed sound tapes (i. e., including atwist through 180 degrees about a longitudinal axis) provided with soundtracks on both sides, and which are played by successive use of groovesat opposite sides, it is proposed in accordance with the invention tocut the master matrix into two halves, to wind up these halves into aroll with the interposition of spacing members, with the sound tracksfacing one another and extending in the same direction, and to iill thespace between the two halves of the master matrix with sprayed orsquirted material, the free ends of the sound tape provided with soundtracks on both sides which is thus produced and then being connectedtogether in crossed fashion.

As tape losses may occur at the cutting and connecting point of themaster matrix tape and of the copy to be produced, it is proposed inaccordance with the invention, in order to allow forI these-losses, toprepare from the original sound 0 tape two master matrices, each ofwhich is cut into two unequal halves, the cutting points of one mastermatrix lying symmetrically with re'v spect to the cutting points of theother master matrix. The two larger master matrix halves, with the soundtracks facing one another and. extending in the same direction, are thenwound up into a roll with the interposition oiv spacing membersand thespace between the two master matrix halves is iilled with sprayed orsquirted material, whereupon the free ends of the tape provided on bothsides with sound tracks which i is thus produced are trimmed andconnected together in crossed fashion.

According to the invention, sound tapes recorded n both sides may alsobe produced by sticking together two sprayed or squirted sound tapeswith the backs facing one another, if necessary after the backs of thetapes have been flattened.

The spacing members are, according to the invention, so dimensioned andarranged that they only lie on the unrecorded edge o! the master matrix,it being advisable to secure them in guides (strip-like elevations,grooves or the like) provided along the edges of the tape form mastermatrix.

The process according to the invention is illus- Y trated in two workingexamples in the drawing,

showing the manner of cutting and positioning the matrix partspreliminary to forming the roll.

Figure 6 is a view corresponding to Fig, l and showing a modified formof roll.

Figure 7 is a sectional view substantially on line 1--1 of Fig. 6.

Figure 8 is a view showing a fragment of a sound tape.

Figure 8a is a section of the same substantially on line Ba- Ba of Fig.8.

Figure 9 is a perspective view of a sound tape formed by joining twosound tapes back-to-back.

Figure 10 is a view 'showing a portion of a matrix with a spacer striphaving spacer blocks attached thereto.

Figures 1 and 2 relate to the duplication of sound tapes havingrecording on one side. A master matrix of tape form is produced from anoriginal sound tape having a recording on one side, for example byelectoplating. This master matrix, which is designated by l in thedrawing, has on its surface, ,instead of the sound grooves of theoriginal sound tape, corresponding elevations 2. The master matrix is,as is shown in Figure 1, wound up into a roll with the interposition ofspacing members 3. The spacing members are only of short length and areof such width that they only lie on the unrecorded edges of the mastermatrix. The height of the spacing members is equal to the thickness ofthe sound tape to be produced. In order that the spacing members may notbe displaced, the master matrix is provided at its edges with strip-likeelevations 4, which engage in corresponding recesses in the spacingmembers and in this way hold the spacing members in position. When themaster matrix is completely wound up, the spaces 5 are filled withmaterial by the spraying or squirting operation.

The duplication of sound tapes recorded on both sides and adapted to beconnected in crossed fashion is shown in Figures 3-7. A master matrix oftape form is again produced from an original sound tape continuouslyrecorded on one side. This master matrix, which is designated by 6, iscut into two halves 6a and 6b as is shown in Figure 3, and these twohalves are disposed one upon the other with the sound tracks facing eachother and extending in the same direction with the leading ends of thehalves adjacent one another, that is to say, the master matrix half 6a,the ends of which are designated by a and b, is placed in juxtapositionto the master matrix half 6b, the ends of which are designated by c andd, as is shown in Figures 3 and 4, and then laid over the master matrixhalf 6b by a hinging movement, so that the edge a1 of the master matrixhalf 6a coincides with the edge a4 of the master matrix half 6b and theedge a2 of the master matrix 6a coincides with the edge a3 of the mastermatrix half 6b, as is shown in Figure 5.'

Betweenthe two master matrix halves 6a. and

6b, spacing members 1 are disposed, which corl respond to the spacingmembers 3 in Figures 1 and 2, whereupon the double master matrix layershown in Figure 5 is wound up into a roll as shown in Figures 6 and 7.When the master matrix has been rolled up, the space 8 between thedouble layers 6a, 6b is filled with material. The sound tape thusproduced with sound tracks on both `sides is then connected at its endsin crossed fashion.

In order t0 avoid cutting losses, it is advisable to prepare from theoriginal sound tape two master matrices which are each cut into twounequal halves, the cutting points of one master matrix lyingsymmetrically with respect to the cutting points of the other mastermatrix, while the two larger master matrix halves are wound up into aroll with the interposition of spacing members, with the sound t'racksfacing one another and extending in the same direction, and the spacebetween the two master matrix halves is filled with material by thespraying or squirting operation.

A section of a sound tape produced in accordance with the invention asdescribed in the foregoing and having sound tracks on both sides isshown in Figures 8 and 8a. The sound tape consists completely of thesprayed or squirted material and has the sound grooves 8 on both sides.The recesses Ill are due to the spacing members 1. The grooves IIcorrespond to the strip-like elevations provided on the edge of themaster matrix for the purpose of holding the spacing members inposition.

Sound tapes having sound tracks on both sides may also be produced bypreparing two sou'nd tapes recorded on one side as shown in Figures 1and 2, and connecting them together back to back, for example byadhesion, as is shown in Figure 9.

The invention is not limited to the constructional examples shown andillustrated, but numerous modications may be made without departing fromthe invention. Thus, for example, as in Figure 10, instead of employingseparate spacing members, a strip 20 provided with projections 2Iserving as spacing members may be employed, the connecting cross pieces22 of which for the spacing members lie outside the master matrix roll.The original sound tape and the master'matrix may also be made widerthan is necessary at the outset and the sound tape consisting oflsprayed or squirted material which is produced in accordance with theinvention may be cut at the edges so as to eliminate the recesses l0caused by the spacing members, in which case a further guide groove maybe provided on both sides of the sound track.

I claim: A

1. A process for the duplication of sound tapes through mechanical soundrecording upon an original sound record tape, which comprises preparingfrom the original sound record tape a master matrix of uniform widthhaving upon its surface multiple parallel ribs corresponding to thesound tracks, spraying or squirting a substance selected from the groupconsisting of moldable artificial resin and cellulose plastics onto thesurface of the master matrix and therewith forming a thin continuouslayer on substantially the entire area thereof, and strippin the layerfrom the master matrix as a flexible duplicate sound tape having aplurality of parallel sound tracks corresponding to the sound tracks ofthe original record tape and being substantially of the same area as thematrix.

2. A process for the duplication of sound tapes through mechanical soundrecording upon an original sound record tape, which comprises preparinga master matrix from the original sound record tape, winding the mastermatrix into a spiral rwith its successive convolutions spaced apart,spraying or squirting a mass selected from the group consisting ofmoldable artificial resin and cellulose plastics into the spiral spacebetween the convolutions of the master m-atrix to fill said space andthereby form a thin continuous spiral layer, and stripping the layerfrom the master matrix as a flexible duplicate sound tape having soundtracks corresponding to the sound tracks of the original record tape.

3. A process forthe duplication of sound tapes through mechanical soundrecording upon an original sound record tape, which comprises preparinga master matrix from the original sound record tape, cutting the mastermatrix transversely to form halves, placing the halves backto-back andwinding them into aV spiral with the sound tracks facing one another andextending in the same direction, the sound track faces of the halvesbeing spaced apart to provide a spiral space, spraying or squirting amass selected from the group consisting of moldable artificial resin andcellulose lplastics into the spiral space between the successiveconvolutions of the master matrix to fill said space and thereby form athin continuous spiral layer, and stripping the layer from the mastermatrix as a flexible duplicate sound tape having sound trackscorresponding to the sound tracks' oftheoriginal record tape.

' tuted by the midf-length of either master matrix,

placing the klonger portions of the master matrices back-to-back andwinding them into a spiral with the sound tracks facing one another andextending in the same direction, the sound track faces of the halvesbeing spaced apart, spraying or squirting a mass selected from the groupconsisting of moldable artificial resin and cellulose plastics int-o thespace between the successive convolutions ofthe master matrix to illlsaid space and thereby form a thin continuous spiral layer, andstripping the layer from the master matrix as a exible duplicate soundtape having sound tracks corresponding to the sound tracks of the'original record tape.

5. A process for the duplication of sound tapes, through mechanicalsound recording of sound lines upon an original sound record tape, whichcomprises preparing a master matrix from the original sound record tape,said master matrix having a width greater than that of the duplicatesound tape to be made, winding the master matrix into a spiral with itssurfaces spaced apart, spraying or squirting a mass selected from thegroup consisting of moldable artificial resin and cellulose plasticsinto the space between the original sound record tape, which comprisespreparing a master matrix from the original sound record tape, saidmaster matrix having a width greater than that of the duplicate soundtape to be made and havingv elevated portions at its edges, winding themaster matrix into a spiral ,3 with its surfaces spaced apart, saidsurfaces being maintained in spaced position by` spacing members held inposition by engagement with said elevations, spraying or squirting amassselected from the group consisting of moldable artificial resin andcellulose plastics into the space between the convolutions of the mastermatrix to nll said space, stripping the, layer from the master matrix asa flexible duplicate sound tape having sound tracks corresponding to thesound tracks of the original record tape, and cutting edge portions fromsaid layer to form the iiexible duplicate sound tape.

'7. A mold for forming duplicate sound record tapes through mechanicalsound recording on an original sound record tape and by means of amaster matrix prepared from said original record tape, comprising aspiral coil formed by winding the master matrix with successiveconvolutions spaced apart, and spacing means including vblocks oflimited dimensions located at the edges of the master matrix and betweensuccessive convolutions thereof, the sound track area of the mastermatrix being free of the blocks and the blocks being spaced apart alongthe length of the master matrix for permitting tape-forming material tobe sprayed 0r squirted into the space between the convolutions forfilling the same.

8. A mold for forming duplicate sound record tapes through mechanicalsound recording on an original sound record tape and by means of amaster matrix prepared from said original record tape, comprising aspiral coil formed by cutting the master matrix transversely to formhalves and winding the halves in back-to-back position with successiveconvolutions spaced apart, and spacing means including blocks of limiteddimensions located at the edges of the master matrix and betweensuccessive convolutions thereof, the sound track area of the mastermatrix being free of the blocks and the blocks being spaced apart alongthe length of the master matrix for permitting tape-forming material tobe sprayed or squirted into the space between the convolutions for llingthe same.

9. A mold for forming duplicate sound record tapes through mechanicalsound recording on versely at lines symmetrical with respect to themid-length thereof and winding the longer sections in back-to-backposition with successive convolutions spaced apart, and spacing meansincluding blocks of limited dimensions located at the edges of themaster matrix and between successive convolutions thereof, the soundtrack area of the master matrix being free of the blocks and the blocksbeing spaced apart along the length of the master matrix for permittingtapeforming material to be sprayed or squirted linto the space betweenthe convolutions for filling the same.

10. A process for the duplication of sound tapes through mechanicalsound recording upon an original sound record tape, which comprisespreparing from the original sound record tape a master matrix havingupon its surface multiple parallel ribs corresponding to the soundtracks,

arranging parts of the master matrix opposite one another to provideanarrow space therebetween, said ribs extending into said space at bothsides thereof, spraying or squirting a substance selected from the groupconsisting of moldable artificial resin and cellulose plastics into saidspace and therewith forming a thin continuous layer having reproductionsupon its opposite surfaces of said parts of the matrix, and strippingthe layer from the parts of the master matrix as a exible duplicatesound tape having a plurality of sound tracks corresponding to the soundtracks oi the original record tape and having substantially the samearea as the matrix.

11. A process for the duplication of sound tapes through mechanicalsound recording upon an original sound record tape, which comprisespreparing from the original sound record tape a master matrix havingupon its surface multiple parallel ribs corresponding to the soundtracks, employing the master matrix to provide a wall o! a mold having anarrow space into which the ribs project, spraying or squirting asubstance selected from the group consisting of moldable articial resinand cellulose plastics into said space and therewith forming a thincontinuous layer having upon its surface the reproduction of saidmatrix, and stripping ythe layer from the 10 master matrix as a ilexibleduplicate sound tape

